Set Starting Voltage:in normal display voltage state,press the button will display start charging voltage;long press for 3s the digital tube will flash;you can start or stop button to set starting up charge voltage value

Set Stop Voltage:in normal display voltage state,press the button will display stoping charge voltage;long press the button for 3s the digital tube will flash;you can start or stop button to set stoping charge voltage value

Factory Reset:in power on state press the start/stop button at the same time,digital tube will display 888;that represents factory reset settings.